The present invention relates to a device for measuring the flatness or planar degree of metal strips under tensile stress, particularly steel strips, during rolling while using measuring rollers, divided into roller sections, and using measuring elements.
Methods and devices for measuring the flatness or deviation from flatness of steel strips are known in the art, cf. "Stahl und Eisen" 1976, No. 1, p. 11/12. With these known methods, that flatness of cold-rolled strips is determined by magnetic measurement of internal strip stresses; on the other hand, it is possible to measure the distribution of specific tensile stresses across the strip width by means of a measuring roller. These known methods and devices permit measuring the flatness of cold-rolled strips during cold rolling, but not the flatness of strips during hot rolling. The magnetic methods cannot be used during hot-rolling because the Curie point is exceeded, while with the other known methods or the associated device, the rotating primary elements in the measuring roller are not suitable or too sensitive for measuring in the hot rolling mill due to the rough operation, including the increased temperatures.
Accordingly, it is an object of the present invention to avoid the disadvantages of the known devices and to provide an arrangement to measure the flatness or deviations from flatness of metal strips, particularly steel strips during hot rolling.
Another object of the present invention is to provide a device of the foregoing character which performs properly during rough operation of a hot rolling mill.
A further object of the present invention is to provide a device, as described, which is substantially simple on construction and may be readily maintained in service.
A still further object of the present invention is to provide a device for measuring the flatness of metal strips with the aforementioned features and having a substantially long operation life.